lme49720 dual high performance, high fidelity …october 2007 lme49720 dual high performance, high...

October 2007

LME49720Dual High Performance, High Fidelity Audio OperationalAmplifierGeneral DescriptionThe LME49720 is part of the ultra-low distortion, low noise,high slew rate operational amplifier series optimized and fullyspecified for high performance, high fidelity applications.Combining advanced leading-edge process technology withstate-of-the-art circuit design, the LME49720 audio opera-tional amplifiers deliver superior audio signal amplification foroutstanding audio performance. The LME49720 combinesextremely low voltage noise density (2.7nV/√Hz) with van-ishingly low THD+N (0.00003%) to easily satisfy the mostdemanding audio applications. To ensure that the most chal-lenging loads are driven without compromise, the LME49720has a high slew rate of ±20V/μs and an output current capa-bility of ±26mA. Further, dynamic range is maximized by anoutput stage that drives 2kΩ loads to within 1V of either powersupply voltage and to within 1.4V when driving 600Ω loads.

The LME49720's outstanding CMRR (120dB), PSRR(120dB), and VOS (0.1mV) give the amplifier excellent oper-ational amplifier DC performance.

The LME49720 has a wide supply range of ±2.5V to ±17V.Over this supply range the LME49720’s input circuitry main-tains excellent common-mode and power supply rejection, aswell as maintaining its low input bias current. The LME49720is unity gain stable. This Audio Operational Amplifier achievesoutstanding AC performance while driving complex loads withvalues as high as 100pF.

The LME49720 is available in 8–lead narrow body SOIC, 8–lead Plastic DIP, and 8–lead Metal Can TO-99. Demonstra-tion boards are available for each package.

Key Specifications

Power Supply Voltage Range ±2.5V to ±17V

THD+N (AV = 1, VOUT = 3VRMS, fIN = 1kHz)

RL = 2kΩ 0.00003% (typ)

RL = 600Ω 0.00003% (typ)

Input Noise Density 2.7nV/√Hz (typ)

Slew Rate ±20V/μs (typ)

Gain Bandwidth Product 55MHz (typ)

Open Loop Gain (RL = 600Ω) 140dB (typ)

Input Bias Current 10nA (typ)

Input Offset Voltage 0.1mV (typ)

DC Gain Linearity Error 0.000009%

Features Easily drives 600Ω loads

Optimized for superior audio signal fidelity

Output short circuit protection

PSRR and CMRR exceed 120dB (typ)

SOIC, DIP, TO-99 metal can packages

Applications Ultra high quality audio amplification

High fidelity preamplifiers

High fidelity multimedia

State of the art phono pre amps

High performance professional audio

High fidelity equalization and crossover networks

High performance line drivers

High performance line receivers

High fidelity active filters

Typical Application

300038k5

Passively Equalized RIAA Phono Preamplifier

© 2007 National Semiconductor Corporation 300038 www.national.com

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Connection Diagrams

30003855

Order Number LME49720MASee NS Package Number — M08A

Order Number LME49720NASee NS Package Number — N08E

Metal Can

300038f3

Order Number LME49720HASee NS Package Number — H08C

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Absolute Maximum Ratings (Notes 1, 2)

If Military/Aerospace specified devices are required,please contact the National Semiconductor Sales Office/Distributors for availability and specifications.

Power Supply Voltage (VS = V+ - V-) 36V

Storage Temperature −65°C to 150°C

Input Voltage (V-) - 0.7V to (V+) + 0.7V

Output Short Circuit (Note 3) Continuous

Power Dissipation Internally Limited

ESD Susceptibility (Note 4) 2000V

ESD Susceptibility (Note 5)

Pins 1, 4, 7 and 8 200V

Pins 2, 3, 5 and 6 100V

Junction Temperature 150°C

Thermal Resistance

θJA (SO) 145°C/W

θJA (NA) 102°C/W

θJA (HA) 150°C/W

θJC (HA) 35°C/W

Temperature Range

TMIN ≤ TA ≤ TMAX –40°C ≤ TA ≤ 85°C

Supply Voltage Range ±2.5V ≤ VS ≤ ± 17V

Electrical Characteristics for the LME49720 (Notes 1, 2) The following specifications apply for

VS = ±15V, RL = 2kΩ, fIN = 1kHz, and TA = 25°C, unless otherwise specified.

Symbol Parameter Conditions

LME49720Units

(Limits)Typical Limit

(Note 6) (Note 7)

THD+N Total Harmonic Distortion + Noise

AV = 1, VOUT = 3Vrms

RL = 2kΩ RL = 600Ω

0.00003

0.00003 0.00009

% (max)

IMD Intermodulation DistortionAV = 1, VOUT = 3VRMS

Two-tone, 60Hz & 7kHz 4:10.00005 %

GBWP Gain Bandwidth Product 55 45 MHz (min)

SR Slew Rate ±20 ±15 V/μs (min)

FPBW Full Power Bandwidth

VOUT = 1VP-P, –3dB

referenced to output magnitude

at f = 1kHz

10

MHz

ts Settling timeAV = –1, 10V step, CL = 100pF

0.1% error range1.2

μs

en

Equivalent Input Noise Voltage fBW = 20Hz to 20kHz 0.34 0.65 μVRMS

(max)

Equivalent Input Noise Densityf = 1kHz

f = 10Hz

2.7

6.4

4.7 nV/√Hz

(max)

in Current Noise Densityf = 1kHz

f = 10Hz

1.6

3.1

pA/√Hz

VOS Offset Voltage ±0.1 ±0.7 mV (max)

ΔVOS/ΔTempAverage Input Offset Voltage Drift vs

Temperature–40°C ≤ TA ≤ 85°C 0.2

μV/°C

PSRRAverage Input Offset Voltage Shift vs

Power Supply VoltageΔVS = 20V (Note 8) 120 110 dB (min)

ISOCH-CH Channel-to-Channel IsolationfIN = 1kHz

fIN = 20kHz

118

112

dB

IB Input Bias Current VCM = 0V 10 72 nA (max)

ΔIOS/ΔTempInput Bias Current Drift vs

Temperature–40°C ≤ TA ≤ 85°C 0.1

nA/°C

IOS Input Offset Current VCM = 0V 11 65 nA (max)

VIN-CM Common-Mode Input Voltage Range +14.1

–13.9

(V+) – 2.0

(V-) + 2.0V (min)

CMRR Common-Mode Rejection –10V<Vcm<10V 120 110 dB (min)

ZIN

Differential Input Impedance 30 kΩCommon Mode Input Impedance –10V<Vcm<10V 1000 MΩ

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Symbol Parameter Conditions

LME49720Units

(Limits)Typical Limit

(Note 6) (Note 7)

AVOL Open Loop Voltage Gain

–10V<Vout<10V, RL = 600Ω 140 125

dB (min)–10V<Vout<10V, RL = 2kΩ 140

–10V<Vout<10V, RL = 10kΩ 140

VOUTMAX Maximum Output Voltage Swing

RL = 600Ω ±13.6 ±12.5

V (min)RL = 2kΩ ±14.0

RL = 10kΩ ±14.1

IOUT Output Current RL = 600Ω, VS = ±17V ±26 ±23 mA (min)

IOUT-CC Instantaneous Short Circuit Current +53

–42

mA

ROUT Output Impedance

fIN = 10kHz

Closed-Loop

Open-Loop

0.01

13

Ω

CLOAD Capacitive Load Drive Overshoot 100pF 16 %

IS Total Quiescent Current IOUT = 0mA 10 12 mA (max)

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.

Note 2: Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. For guaranteed specificationsand test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristicsmay degrade when the device is not operated under the listed test conditions.

Note 3: Amplifier output connected to GND, any number of amplifiers within a package.

Note 4: Human body model, 100pF discharged through a 1.5kΩ resistor.

Note 5: Machine Model ESD test is covered by specification EIAJ IC-121-1981. A 200pF cap is charged to the specified voltage and then discharged directly intothe IC with no external series resistor (resistance of discharge path must be under 50Ω).Note 6: Typical specifications are specified at +25ºC and represent the most likely parametric norm.

Note 7: Tested limits are guaranteed to National's AOQL (Average Outgoing Quality Level).

Note 8: PSRR is measured as follows: VOS is measured at two supply voltages, ±5V and ±15V. PSRR = | 20log(ΔVOS/ΔVS) |.

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Typical Performance Characteristics

THD+N vs Output VoltageVCC = 15V, VEE = –15V

RL = 2kΩ

300038k6


RL = 2kΩ

300038k7


RL = 2kΩ

300038k8

THD+N vs Output VoltageVCC = 2.5V, VEE = –2.5V

RL = 2kΩ

300038i4


RL = 600Ω

300038k9


RL = 600Ω

300038l0

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RL = 600Ω

300038l1


RL = 600Ω

300038i6


RL = 10kΩ

300038l2


RL = 10kΩ

300038l3


RL = 10kΩ

300038l4


RL = 10kΩ

300038i5

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THD+N vs FrequencyVCC = 15V, VEE = –15V, VOUT = 3VRMS

RL = 2kΩ

30003863


RL = 2kΩ

30003862


RL = 2kΩ

30003864


RL = 600Ω

30003859


RL = 600Ω

300038k3


RL = 600Ω

30003860

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RL = 10kΩ

30003867


RL = 10kΩ

30003866


RL = 10kΩ

30003868

IMD vs Output VoltageVCC = 15V, VEE = –15V

RL = 2kΩ

300038e6


RL = 2kΩ

300038e5

IMD vs Output VoltageVCC = 2.5V, VEE = –2.5V

RL = 2kΩ

300038e4

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RL = 2kΩ

300038e7


RL = 600Ω

300038e2


RL = 600Ω

300038e0


RL = 600Ω

300038e3


RL = 600Ω

300038e1


RL = 10kΩ

300038f1

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RL = 10kΩ

300038f0


RL = 10kΩ

300038f2


RL = 10kΩ

300038l6

Voltage Noise Density vs Frequency

300038h6

Current Noise Density vs Frequency

300038h7

Crosstalk vs FrequencyVCC = 15V, VEE = –15V, VOUT = 3VRMS

AV = 0dB, RL = 2kΩ

300038c8

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AV = 0dB, RL = 2kΩ

300038c9


AV = 0dB, RL = 2kΩ

300038c6


AV = 0dB, RL = 2kΩ

300038c7


AV = 0dB, RL = 2kΩ

300038d0


AV = 0dB, RL = 2kΩ

300038d1

Crosstalk vs FrequencyVCC = 2.5V, VEE = –2.5V, VOUT = 1VRMS

AV = 0dB, RL = 2kΩ

300038n8

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AV = 0dB, RL = 600Ω

300038d6


AV = 0dB, RL = 600Ω

300038d7


AV = 0dB, RL = 600Ω

300038d4


AV = 0dB, RL = 600Ω

300038d5


AV = 0dB, RL = 600Ω

300038d8


AV = 0dB, RL = 600Ω

300038d9

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AV = 0dB, RL = 600Ω

300038d2


AV = 0dB, RL = 10kΩ

300038o0



300038n7



300038n9



300038n6



300038n5

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300038n3



300038n4

PSRR+ vs FrequencyVCC = 15V, VEE = –15V

RL = 10kΩ, f = 200kHz, VRIPPLE = 200mVpp

300038p2

PSRR- vs FrequencyVCC = 15V, VEE = –15V


300038p5



300038p3



300038p6

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RL = 600Ω, f = 200kHz, VRIPPLE = 200mVpp

300038p1



300038p4



300038p8

PSRR– vs FrequencyVCC = 12V, VEE = –12V


300038q1



300038p9



300038q2

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300038p7



300038q0



300038r0



300038r3



300038r1



300038r4

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300038q9



300038r2

PSRR+ vs FrequencyVCC = 2.5V, VEE = –2.5V


300038q4

PSRR– vs FrequencyVCC = 2.5V, VEE = –2.5V


300038q7



300038q5



300038q8

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300038q3



300038q6

CMRR vs FrequencyVCC = 15V, VEE = –15V

RL = 2kΩ

300038g0


RL = 2kΩ

300038f7


RL = 2kΩ

300038g3

CMRR vs FrequencyVCC = 2.5V, VEE = –2.5V

RL = 2kΩ

300038f4

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RL = 600Ω

300038o9


RL = 600Ω

300038f9


RL = 600Ω

300038g5


RL = 600Ω

300038f6


RL = 10kΩ

300038o8


RL = 10kΩ

300038f8

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RL = 10kΩ

300038g4


RL = 10kΩ

300038f5

Output Voltage vs Load ResistanceVDD = 15V, VEE = –15V

THD+N = 1%

300038h1


THD+N = 1%

300038h0


THD+N = 1%

300038h2

Output Voltage vs Load ResistanceVDD = 2.5V, VEE = –2.5V

THD+N = 1%

300038g9

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Output Voltage vs Supply VoltageRL = 2kΩ, THD+N = 1%

300038j9

Output Voltage vs Supply VoltageRL = 600Ω, THD+N = 1%

300038j8

Output Voltage vs Supply VoltageRL = 10kΩ, THD+N = 1%

300038k0

Supply Current vs Supply VoltageRL = 2kΩ

300038j6

Supply Current vs Supply VoltageRL = 600Ω

300038j5

Supply Current vs Supply VoltageRL = 10kΩ

300038j7

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Full Power Bandwidth vs Frequency

300038j0

Gain Phase vs Frequency

300038j1

Small-Signal Transient ResponseAV = 1, CL = 10pF

300038i7

Small-Signal Transient ResponseAV = 1, CL = 100pF

300038i8

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Application Information

DISTORTION MEASUREMENTS

The vanishingly low residual distortion produced byLME49720 is below the capabilities of all commercially avail-able equipment. This makes distortion measurements justslightly more difficult than simply connecting a distortion me-ter to the amplifier’s inputs and outputs. The solution, how-ever, is quite simple: an additional resistor. Adding thisresistor extends the resolution of the distortion measurementequipment.

The LME49720’s low residual distortion is an input referredinternal error. As shown in Figure 1, adding the 10Ω resistorconnected between the amplifier’s inverting and non-inverting

inputs changes the amplifier’s noise gain. The result is thatthe error signal (distortion) is amplified by a factor of 101. Al-though the amplifier’s closed-loop gain is unaltered, the feed-back available to correct distortion errors is reduced by 101,which means that measurement resolution increases by 101.To ensure minimum effects on distortion measurements,keep the value of R1 low as shown in Figure 1.

This technique is verified by duplicating the measurementswith high closed loop gain and/or making the measurementsat high frequencies. Doing so produces distortion compo-nents that are within the measurement equipment’s capabili-ties. This datasheet’s THD+N and IMD values were generat-ed using the above described circuit connected to an AudioPrecision System Two Cascade.

300038k4

FIGURE 1. THD+N and IMD Distortion Test Circuit

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The LME49720 is a high speed op amp with excellent phasemargin and stability. Capacitive loads up to 100pF will causelittle change in the phase characteristics of the amplifiers andare therefore allowable.

Capacitive loads greater than 100pF must be isolated fromthe output. The most straightforward way to do this is to put

a resistor in series with the output. This resistor will also pre-vent excess power dissipation if the output is accidentallyshorted.

30003827

Complete shielding is required to prevent induced pick up from external sources. Always check with oscilloscope for power line noise.

Noise Measurement CircuitTotal Gain: 115 dB @f = 1 kHz

Input Referred Noise Voltage: en = V0/560,000 (V)

RIAA Preamp Voltage Gain, RIAADeviation vs Frequency

30003828

Flat Amp Voltage Gain vsFrequency

30003829

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TYPICAL APPLICATIONS

NAB Preamp

30003830

AV = 34.5

F = 1 kHz

En = 0.38 μV

A Weighted

NAB Preamp Voltage Gainvs Frequency

30003831

Balanced to Single Ended Converter

30003832

VO = V1–V2

Adder/Subtracter

30003833

VO = V1 + V2 − V3 − V4

Sine Wave Oscillator

30003834

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Second Order High Pass Filter(Butterworth)

30003835

Illustration is f0 = 1 kHz

Second Order Low Pass Filter(Butterworth)

30003836

Illustration is f0 = 1 kHz

State Variable Filter

30003837

Illustration is f0 = 1 kHz, Q = 10, ABP = 1

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AC/DC Converter

30003838

2 Channel Panning Circuit (Pan Pot)

30003839

Line Driver

30003840

Tone Control

300038p0

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Illustration is:

fL = 32 Hz, fLB = 320 Hz

fH =11 kHz, fHB = 1.1 kHz

30003842

RIAA Preamp

30003803

Av = 35 dB

En = 0.33 μV

S/N = 90 dB

f = 1 kHz

A Weighted

A Weighted, VIN = 10 mV

@f = 1 kHz

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Balanced Input Mic Amp

30003843

Illustration is:

V0 = 101(V2 − V1)

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10 Band Graphic Equalizer

30003844

fo (Hz) C1 C2 R1 R2

32 0.12μF 4.7μF 75kΩ 500Ω64 0.056μF 3.3μF 68kΩ 510Ω

125 0.033μF 1.5μF 62kΩ 510Ω250 0.015μF 0.82μF 68kΩ 470Ω500 8200pF 0.39μF 62kΩ 470Ω1k 3900pF 0.22μF 68kΩ 470Ω2k 2000pF 0.1μF 68kΩ 470Ω4k 1100pF 0.056μF 62kΩ 470Ω8k 510pF 0.022μF 68kΩ 510Ω

16k 330pF 0.012μF 51kΩ 510Ω

Note 9: At volume of change = ±12 dB

Q = 1.7

Reference: “AUDIO/RADIO HANDBOOK”, National Semiconductor, 1980, Page 2–61

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Revision History

Rev Date Description

1.0 03/30/07 Initial release.

1.1 05/03/07 Put the “general note” under the EC table.

1.2 10/22/07 Replaced all the PSRR curves.

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Physical Dimensions inches (millimeters) unless otherwise noted

Narrow SOIC PackageOrder Number LME49720MANS Package Number M08A

Dual-In-Line PackageOrder Number LME49720NANS Package Number N08E

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TO-99 Metal Can PackageOrder Number LME49720HANS Package Number H08C

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